DE102018102903A1 - Method for producing a structural component from a high-strength alloy material - Google Patents

Abstract

A method for producing a structured structural component 9 from a high-strength alloy material is determined by subdividing the structural component 9 into at least two component sections that differ in their requirement profile during subsequent use, wherein one component section is used in the structural component 9 during installation With regard to occurring loads, higher requirement profile and the at least one further component section 8 must satisfy a lower requirement profile, and - in a first production step for creating the component section with the higher requirements, a blank 2 is brought by forging partially into a near-net shape or final contour-precise shape at least one subsequent step on at least one by the forging step not yet brought into a near net shape or final contour precise surface area as a substrate by a generative Fertigungsverfah Ren metallic alloy material for forming the at least one component portion 8 is applied with the lower requirement profile to bring these areas of the forged component portion in a final kontontähere shape and then the semi-finished product produced in this way as a completed preform 7 one or more stages in its final contour is brought.

Description

The invention relates to a method for producing a structured structural component from a high-strength alloy material.

Structured structural components are components that are intrinsically structured and, as such, involved in building a larger structure. Such structural components are used for example in aerospace engineering, such as ribs, frames, guide rails for wing flaps and the like. High-strength alloy materials such as ultra-high-strength aluminum materials or titanium materials are used for this purpose. Structural components made of titanium materials are increasingly substituting those of ultra-high-strength aluminum alloys, since these tend to corrode in contact with carbon-fiber-reinforced plastic components. Increasingly, carbon fiber reinforced plastic components are used in aircraft. Such a structural member made of a titanium material is manufactured by machining a forged preform. Forging in the (α + β) region is preferred for precision isothermal forging in the β-region of the alloy due to the lower process temperatures and the lower plant outlay. Due to the high deformation resistance of this material - the same applies in principle to other high-strength alloy materials, such as nickel-based alloys and cobalt-based alloys - an often very high oversize is required because the forging process acts globally on the workpiece. Against the background of increasingly complex structural components, the tool costs, the tool wear and the susceptibility to errors increase in the production of such structured structural components. For this reason, the formation of the final contour is shifted into downstream machining processes, which in turn results in the fact that the material utilization is sometimes only 40% or less, in some components only about 10% of the material originally used. Apart from the high machining costs, the low material utilization makes the manufactured structural components more expensive.

Based on this discussed prior art, the invention is therefore based on the object of proposing a method for producing a structured structural component from a high-strength alloy material, for example a titanium alloy, with which such a structural component can be produced not only by using a forging step, but that the disadvantages of the prior art are at least largely avoided.

• - das zu erstellende Strukturbauteil in zumindest zwei sich bezüglich ihres Anforderungsprofiles bei der späteren Verwendung unterscheidende Bauteilabschnitte unterteilt wird, wobei ein Bauteilabschnitt bei der Verwendung des Strukturbauteils einem in Bezug auf auftretende Belastungen höheren Anforderungsprofil und der zumindest eine weitere Bauteilabschnitt einem geringeren Anforderungsprofil genügen muss, und
• - in einem ersten Fertigungsschritt zum Erstellen des Bauteilabschnittes mit den höheren Anforderungen ein Rohling durch Schmieden bereichsweise in eine endkonturnahe oder endkonturgenaue Form gebracht wird,
• - in zumindest einem nachfolgenden Schritt auf zumindest einem durch den Schmiedeschritt noch nicht in eine endkonturnahe oder endkonturgenaue Form gebrachten Oberflächenbereich als Substrat durch ein generatives Fertigungsverfahren metallisches Legierungsmaterial zum Ausbilden des zumindest einen Bauteilabschnittes mit dem geringeren Anforderungsprofil aufgebracht wird, um auch diese Bereiche des geschmiedeten Bauteilabschnitts in eine endkonturnähere Form zu bringen und
• - anschließend das auf diese Weise hergestellte Bauteilhalbzeug als komplettierte Vorform ein- oder mehrschrittig in seine Endkontur gebracht wird.

This object is achieved according to the invention by an aforementioned, generic method, in which

• - The structural component to be created in at least two with respect to their requirement profile in the subsequent use different component sections is divided, wherein a component portion must comply with the use of the structural component in relation to occurring loads higher requirement profile and the at least one further component section a lower requirement profile, and
• - In a first manufacturing step for creating the component section with the higher requirements, a blank is brought by forging partially in a near net shape or final contour accurate shape,
• - Is applied in at least one subsequent step on at least one not brought by the forging step in a near net shape or final contour exact surface area as a substrate by a generative manufacturing process metallic alloy material for forming the at least one component portion with the lower requirement profile to these areas of the forged component portion into a near-net shape and bring
• - Then the semifinished product produced in this way as a completed preform one or more stages is brought into its final contour.

The term "structural component" used in the context of this embodiment is understood to mean any component which has a structure and has a component section which is formed by forging and at least one further component section which is applied to the forged component section. Thus, the term "structural component" is to be understood as meaning components which are structural components in the narrower sense and are thus involved in the construction of larger structures, such as ribs or ribs or other components as parts of aircraft or other structured structural components that do not Structure of a larger structure can be used, such as rotary body, such as blades for turbines or the like.

The structural component produced in accordance with this method is the result of different manufacturing or shaping processes, wherein different component sections of the structural component are produced using different process routes, so that such a structured structural component can be addressed with regard to its production as a hybrid structural component. It is important that prior to the actual manufacture of such a structural component this is subdivided into different component sections, wherein the component sections differ by the requirement profile respectively, for example with respect to the mechanical requirement profile applied to individual component sections. For example, a central component section must satisfy a higher mechanical load than other component sections formed thereon. The component sections, to which a higher, in particular mechanical requirement profile is provided, are formed by forging close to final contour or final contour precision, at least to the extent that as little material as possible has to be removed by machining in order to set the final contour. In the case of these structural components, these component sections typically represent the core segment of such a structural component. At least one component section, typically a plurality of component sections, is formed on this core segment formed by forging and acts only on a smaller mechanical load during the subsequent use of the structural component. Therefore, these component sections must only satisfy a lower requirement profile. This one or more further component sections are applied or formed by a generative manufacturing process on a region of the lateral surface of the core segment. These may be extensions, such as connection points, ribs, receptacles for components, such as sensors or the like. These component sections, which are applied by a generative manufacturing method, can have a local extension or can also be formed circumferentially both in the transverse direction and in the longitudinal direction of the core segment over all or part of this extension. These component sections are mostly responsible for the shape complexity of such structural components. Due to the generative application of high-strength alloy material, complicated geometries can be produced without great oversize, especially those that can not be formed by forging, such as undercut sections. In this respect, certain areas of the lateral surface of the forged component section form the substrate on which the additively manufactured component sections are produced.

A generative manufacturing process is used in which metal powder or metal wire is fused by supplying energy. Typically, to create the raw form for these areas by means of the additive manufacturing process, they are made from an alloy powder or wire similar to that of the forged blank - the forged core segment. To build up the component sections formed by a generative manufacturing method, it is also possible to use alloy variants or another metal alloy. In such a case, care must be taken that there is a proper joining connection between the substrate and the material applied thereto by the generative method. The additive manufacturing process may be performed, for example, as laser cladding or by electron beam deposition welding, just to name a few of the possible methods. By means of one or more such steps, the component sections, which have not yet been brought by the forging process into a near-net-shape or final contour-precise form, are built into a near net shape. In a subsequent one-step or multi-step machining step, these generatively constructed component sections can be brought into their final contour. In the same processing step, it is also possible to bring the one or more component parts of the forged semi-finished product forged into its final contour. These processing steps can be, for example, a forging step, with which the generatively generated regions are deformed to a certain extent, and / or a machining operation. By a forming step with only a small degree of deformation, the microstructure is optimized for a subsequent heat treatment to homogenize the microstructure. In addition, the voltage pickup of this component section is improved by such a step. Depending on the configuration of the semifinished product or of the component or sections to be brought into its final contour, the machining may be, for example, a form milling, turning, drilling or the like. A combination of these measures is possible, as well as the subsequent introduction of a low degree of deformation.

The above-described manufacturing method can be followed by a heat treatment for the purpose of homogenization of the structure of the forged component section as well as those component sections that have been produced by a generative manufacturing process, and / or cold forming, such as stretching of the structural component brought into its final contour.

In such structural components, which are mainly used in aerospace technology, such a structural component combines the positive properties of a blank formed by forging with the properties of a manufactured by a generative manufacturing process component with respect to the manufacturable by such a method complex geometries. Thus, the areas produced by a generative manufacturing process can have geometries that can not be produced by forging, even by multiple forging, for example by relatively long flow paths or by the fact that these geometries can not be produced by forging, such as undercuts. Such a structural component will be divided, with respect to the division of the regions into forged regions and those which are constructed by an additive manufacturing method, typically such that the regions of the structural component which are exposed to higher, in particular dynamic, stresses are component parts which have been forged during the application of the structural component or at least have a forged core. Is exploited here for especially against such loads particularly resistant forgings.

In the investigations that led to the subject matter of this invention, it was initially necessary to ignore the prevailing teaching that such a structural component structured by specific geometries must be manufactured from a single piece in order to meet the requirements imposed on the structural component. Only this opened the way to a division of the structural component in component sections with different requirement profiles and to the subject of the claimed method. Thus, for example, in a structural member having one or more stiffening ribs to achieve desired strength properties, it is sufficient if the base surface or root of such rib is formed by forging together with the adjacent core segment but the rib formation is first height-adjusted by a generative manufacturing process constructed and then brought into the desired final contour. The same applies, for example, for the formation of connection points of certain geometry, which may have such a structural component. Numerous other embodiments are conceivable.

The connection of a component section produced by additive manufacturing can be provided on a base formed by the preceding forging step, the upper side of which forms the substrate surface. By such an integrally formed on the core segment base, the actual core segment as a component section, which should withstand the requirements of a higher requirement profile, protected by thermal interference or near-surface material mixing as a result of generative manufacturing process, so that set by the forging material and structural properties in the actual core segment not or at least not significantly changed by the typically locally executed generative manufacturing step. In this respect, one will control the generative manufacturing step with respect to its heat input into the forged core segment, wherein on the core segment molded socket, as described above can make their contribution to this. Moreover, such a socket reduces the notch sensitivity in the transition region.

The forging step is typically carried out as a one-step forging step. This includes repressing after a short vent opening of the die. In this context, one-stage means that the forming takes place in a single die. Also a multi-stage executed forging step is possible, but can often be avoided by a clever design of the structural component with respect to the formed by forging component sections and the generatively constructed component sections. Since this does not take the entire shape of the structural component, the dies used for forging are also not subjected to excessive load (leaching), so that the service life is correspondingly longer. This also has a positive effect on the tolerances to be maintained in the production of such structural components in mass production.

This method also opens up the possibility of designing a structural component in different variants. The identical part of the different variants is produced by the forging process. Thus, for all variants of such a structural component, the forged semi-finished product is the identical part to which material for the variant formation is applied in the component sections which are not yet near net shape or in the shape of a final contour by at least one additive manufacturing method. Both the areas and the shape of the component sections of the structural component constructed by the generative manufacturing method or methods can differ in the individual variants. This not only reduces material usage, but also makes the entire production chain more cost-effective.

In such production hybrid structural components, the one or more less loaded and produced by a generative manufacturing process component sections for weight reduction can be optimized in a way that this could not be achieved in the conventional manner or only with disproportionate effort. By way of example, the formation of a hollow structure may be mentioned here. Such a hollow structure can be made without sacrificing the load capacity of this component section due to the requirements placed on it. The result is a reduced use of material and a reduced weight of the finished structural component. A lesser one Material use is a particular advantage, especially for structural components with relatively high material costs.

The hybrid production method also allows for a design of the component sections produced by generative manufacturing processes on the forged semi-finished product - the forged core segment - with an alloy that is different from the alloy of the forged semi-finished product. This may be an alloy having a different composition of its alloy components. In this respect, the material used for the component sections produced by additive manufacturing processes can be selected specifically with regard to the requirements placed on these areas of the structural component in the intended application.

By using different material compositions in the construction of a component portion to be created by a generative manufacturing process, within it, for example, material gradients and thus gradients with respect to, for example, one or more strength parameters can be generated. Such a component can also be addressed as a material-hybrid component.

The generative manufacturing method for producing a component section on the forged semi-finished product also allows powder particles or grains of a material to be incorporated therein, which have special properties independent of the alloy to be produced. For example, this material may be one which evaporates at the fusion temperature to melt the powder particles, in order to produce a certain porosity in a component section of the structural component constructed in this way. Can be stored in this way also in the manufactured by the additive manufacturing process component section solid lubricants, if it is the part to be generated, for example, such a part of a bearing, for example, to represent a bearing bush.

It is regarded as advantageous if those regions of the forged semi-finished product - the substrate - are pretreated with respect to the at least one component section to be produced thereon by means of a generative production method and prepared for the generative production process. This can be, for example, a mechanical pretreatment, for example to increase the contact surface of the substrate to the material to be applied thereto. The additive manufacturing method according to one embodiment is a laser or electron beam deposition welding. In such a case, prior to the first deposition of the particles to be fused by the laser or electron beam, the substrate surface may be subjected to a blasting treatment to roughen this surface area, thereby increasing the bonding surface area. Such a step is preferably carried out immediately before the beginning of the build-up welding to produce the areas to be applied to the substrate surface, since this area is then preheated at the same time in preparation for the generative production step. As a preparatory measure for the near net shape construction of such a region by means of a generative manufacturing process, a corresponding heating of the surface region of the substrate can also be used alone. On its own or in combination with one of the two aforementioned pretreatment measures, the substrate surface can also be chemically pretreated, for example to remove surface contaminants or lubricants entrained from the forging sink.

If, following the near-net shape training of or produced by a generative manufacturing process component sections on the forged semi-finished to be brought to their final shape or in a final kontkontähherere form by forging, the superficial irregularities, the laser deposition welding, as well as the electron beam welding as Generative manufacturing process involves using lubricating pockets to control material flow.

The setting of the final contour of the structural component can be one or more stages.

According to one embodiment, a titanium alloy, in particular a (α + β) titanium alloy, such as a Ti-6Al-4V alloy, is used for the forging blank.

• 1: Eine Figurenfolge, die die Ergebnisse einzelner Herstellungsschritte zum Herstellen eines strukturierten Strukturbauteils mit dem erfindungsgemäßen Verfahren zeigt, und
• 2: die Herstellung eines weiteren Strukturbauteils gemäß einer anderen Ausgestaltung.

The invention is described below with reference to an embodiment with reference to the accompanying figures. Show it:

• 1 A sequence of figures which shows the results of individual production steps for producing a structured structural component with the method according to the invention, and
• 2 : the production of a further structural component according to another embodiment.

The sequence of figures of 1 shows under ( 1 ) a blank 1 of a Ti-6Al-4V alloy as an exemplary high-strength alloy material. At the blank 1 it is a cast billet. In the illustrated Embodiment is the blank 1 in a first step ( 2 ) in a blacksmith preform 2 brought. In the illustrated embodiment, the casting blank 1 forged and a section of the blank 1 have been bent by 90 degrees relative to the remaining portion with a radius, so that in a side view of the forging blank is L-shaped. The blank has an (α + β) -type.

To prepare the forging of this forging blank 2 This is heated to its forging temperature, placed in a die and in the preform shown in (3) 3 forged. Through the forging process is the shorter leg 4 of forging blank 2 in a square shape 5 has been brought. This connects with the interposition of transition areas to the arc section. In the longer thighs of the forging blank 2 are under extension of its length two constrictions 6 . 6.1 introduced by the forging step. The preform created by the forging 3 is already shaped near net shape in some sections. This preform is in the illustrated embodiment, the core segment of the future structural component. This core segment is that part of the component, which must satisfy a higher mechanical requirement profile than the other component sections described below. This applies in the illustrated embodiment, in particular with respect to its dynamic load capacity.

That from the blank 1 structural component to be manufactured has a relation to the preform 3 much more complex shape. In order to create this more complex shaping, the preform will become in those areas 3 , which are to carry the further structures raw forms, constructed by generative laser deposition welding in the illustrated embodiment. It is understood that other deposition welding methods can also be used. The build-up welding has been carried out with respect to the introduced heat so that the heat input into the core segment is locally only very low and also a material mixing is limited only to a superficial edge zone of the substrate. The generative manufacturing completed preform 7 is in step ( 4 ) the 1 shown. The component sections produced or constructed by the generative method - the raw forms for the further structures - are identified by the reference numeral 8th indicated. In the illustrated embodiment, the regions produced by the generative process are 8th made of alloy powder of the same alloy, from which also the blank 1 is made. On the square leg 5 the preform 3 are on opposite surfaces two cylindrical areas 8th been built by the generative manufacturing process. On the lateral surface of the longer leg of the preform 3 frusto-conical bodies have been constructed by the generative process. In the illustrated embodiment, the to the lateral surface of the preform 3 adjacent sections of this conical body designed as a hollow body. The generative manufacturing process was performed as laser deposition welding.

The final contour of the completed preform 7 with its built-up by the generative manufacturing method described component sections 8th takes place in the illustrated embodiment by a machining (see step (s. 5 )). The component sections 8th forming raw forms are shaped by milling into their in ( 5 ) brought final contour shown. In this processing step, those areas of the completed preform also become 7 brought into their final shape, which are not formed by the final forging final contour.

In the structural component 9 it is a fictitious structural component.

Essential in this structural component 9 is that through the forged preform 3 shaped core segment can be exposed as a component section of an increased mechanical stress. Because the L-shape of the structural component 9 is formed by forging, this core segment of the structural component is sufficient 9 even high demands placed on it easily. This is also the case due to the requirement profile placed on the core segment. The component sections generated by the generative manufacturing process 8th and the resulting from shaping milling in final contour extensions must in the use of the structural component 9 do not meet these requirements. These can also be exposed to higher loads, but do not have to meet the load requirements of the structural component 9 in the sections of its L-shaped preform. If, as is the case with previously known methods, the structural component 9 would be made by forging a preform and subsequent machining, this would be possible only with a low material utilization, which would not only be more expensive, but also more expensive.

Preceding the above-described manufacturing steps is a division of the structural component 9 in terms of their mechanical requirement profile different component sections, and that by the preform 3 formed core segment as a first component portion, which must meet a higher requirement profile, and molded thereon second component sections 8th who do not have to meet this high profile of requirements.

After the structural component 9 has been brought into its final contour, this is subjected to a heat treatment to homogenize the microstructure.

In the structural component 9 of the illustrated embodiment is one of several variants, which is characterized by the number of built-up by the generative manufacturing process component sections 8th differ. In the illustrated structural component 9 it is that of the several variants, which unites all of the possible variants that differ in terms of the number of extensions. Thus, a further variant not shown in the figures has the square shape 5 of the shorter leg only a single applied by the generative process component section 8th and brought by the form milling in the final contour extension. In a further variant, this leg of the structural component 9 no extensions on. Other variants consist in a different interpretation of the longer leg molded extensions.

A particular advantage of this concept is that all variants can be produced on one and the same production line with one and the same tools.

2 showed one of the sequence of figures of 1 corresponding sequence of figures representing the hybrid production of another structural component 9.1 , In the manufacturing process of 2 After the division of the structural component in different with respect to their requirement profile component sections the same steps ( 1 ) to ( 5 ) performed as this previously in the embodiment of 1 has been explained. For this reason, the same features or parts with the same reference numerals, supplemented by a ". 1 "Marked. Also the structural component 9.1 itself is the above-described structural component 9 the 1 very similar. The blank 1.1 in the embodiment of the 2 has been made from the same titanium alloy as the blank 1 of the embodiment of 1 , The structural component 9.1 differs from the structural component 9 through its structuring, because the extensions - and accordingly the component areas created by generative manufacturing 8.1 . 8.2 - in contrast to the structural component 9 are not arranged opposite each other. Furthermore, the structural component differs 9.1 from the structural component 9 by shaping the forged preform 3.1 , By the forging process, one of each of the core segment of the preform is 3.1 projecting pedestal for forming a root area or a transition area. The upper side of the pedestals represents the substrate surface onto which the component sections to be produced generatively 8.1 . 8.2 be applied. In 2 these pedestals are identified by the reference numeral 10 indicated. On this pedestal 10 is used to make the completed preform 7.1 Applied by way of generative manufacturing process, the material. By creating the final contour of the structural component 9.1 Form milling step performed are, as especially on the extensions that are formed on the square legs, also parts of the approach has been removed. Advantageous in such an embodiment of the forged completed preform 7.1 in that the attachment of the generatively applied material is spaced from the fiber path of the forged preform in its core.

In this embodiment, the component portion 8.2 designed as a hollow body, as shown by the sectional views of this component section 8.2 in the steps ( 4 ) and ( 5 ) the 2 shown.

After forming the structural component 9.1 in its final contour this is also heat treated and formed with low degree of deformation.

The embodiments described above serve to explain the invention. Without departing from the scope of the applicable claims, numerous other possibilities for a person skilled in the art to implement the invention, without this having to be explained in detail in the context of this embodiment.

LIST OF REFERENCE NUMBERS

1, 1.1

blank

2

blacksmith blank

3, 3.1

preform

4

leg

5

Square shape

6, 6.1

constriction

7, 7.1

completed preform

8, 8.1, 8.2

component section

9, 9.1

structural component

10

base

Claims (13)

Method for producing a structured structural component (9, 9.1) from a high-strength alloy material, characterized in that - the structural component (9, 9.1) to be created is subdivided into at least two component sections that differ in respect of their requirement profile during later use, wherein a component section ( 3, 3.1) in the use of the structural component (9, 9.1) with respect to occurring Stresses higher requirement profile and the at least one further component section (8, 8.1, 8.2) must meet a lower requirement profile, and - in a first manufacturing step for creating the component section (3, 3.1) with the higher requirements a blank (2) by forging partially in a near net shape or final contour exact shape is brought, - in at least one subsequent step on at least one by the forging step not yet brought into a near net shape or final contour exact surface area as a substrate by a generative manufacturing process metallic alloy material for forming the at least one component portion (8, 8.1, 8.2 ) is applied with the lower requirement profile, in order to bring these areas of the forged component portion in a near-net shape and form - then the semi-finished product produced in this way as a completed preform (7, 7.1) one or more stages in s a final contour is brought. Method according to Claim 1 , characterized in that differ the requirement profile of the component section (3, 3.1) with the higher requirement profile and that of the one or more component sections (8, 8.1, 8.2) with the lower requirement profile by the mechanical load capacity. Method according to Claim 1 or 2 , characterized in that the structural component (9, 9.1) is made of a titanium alloy, an aluminum alloy, a cobalt-based alloy or a nickel-based alloy. Method according to one of Claims 1 to 3 , characterized in that the generative manufacturing process laser deposition welding is performed using solid particles. Method according to one of Claims 1 to 4 , characterized in that for the generative manufacturing step, the same alloy is used, from which also the blank (2) is made. Method according to one of Claims 1 to 4 , characterized in that an alloy different from the alloy of the blank is used for the additive manufacturing step. Method according to one of Claims 1 to 6 Characterized in that a plurality of generative manufacturing steps are carried out for the net-shape forming of the final contour or not endkonturgenau molded by the forging step component portions. Method according to Claim 7 , characterized in that between two generative manufacturing steps, the generatively formed component sections are formed by forging in a near final contour shape and that the subsequent generative manufacturing step is performed on the formed material of the previous generative manufacturing step. Method according to one of Claims 1 to 8th , characterized in that prior to performing a generative manufacturing step, the application surface of the substrate is pretreated for the generative manufacturing step. Method according to one of Claims 1 to 9 , characterized in that the near-net shape component sections (8, 8.1) of the completed preform are brought by forging and / or by machining in their final contour. Method according to one of Claims 3 to 10 , characterized in that a (α + β) -Titanlegierung is used as the titanium alloy. Method according to Claim 11 , characterized in that a Ti-6AI-4V alloy is used as the titanium alloy. Method according to one of Claims 1 to 12 , characterized in that the structural component (9, 9.1) is one of several variants of this structural component, whereby the identical parts of the variants are produced by the forging step and the variant formation takes place by the component or sections (8, 8.1, 8.2) formed by generative production ,

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